x CAMEL-LIKE PERISSODACTYLES 267 three-toed. It was intermediate between a Tapir and a Rhinoceros in size. It has been shown, too, from casts of the interior of the skull, that the cerebral hemispheres are much less convoluted than were those of Titanotherium. Belated to Palaeosyops is another primitive Titanothere, the genus TelmatotJierium. This is also Eocene, from the Uinta Basin, the uppermost of Eocene strata. The skull of these creatures was rather elongated, and not unlike that of a Titano- there in general aspect. The dentition was complete and the canines not very large. The horns, which acquire so prodigious a development in the later Titanotheres, are just recognisable in at any rate many species of this genus Tel'matotJieriwrn^ the name being thus by no means an apt one. Better was that proposed by Dr. Wortman, of Manteoceras or " prophet horned/* The horns are small elevations upon the frontals just at the junction of these with the nasals, and., indeed, lying partly upon the latter bones. In T. cornutum the horns are chiefly borne upon the very long nasals., whose size contrasts with the same bones in the more Mghly- developed Titanotheriu^n. It appears to be quite possible that TitanotJierium was evolved from the genus SUB-ORDER 9, LITOPTERKA. Whether the MaerancheBiiclae should be considered as a separate group of Ungulata is a matter of dispute. Cope placed them in a special order of Ungulates which he called Iltopterna. Zittel, on the other hand, regards them as definitely Perissodaetyles. One curious point of resemblance to existing Horses is shown - that is the presence of a pit in the incisor teeth. This matter seems to be so important as to need a placing of these forms in the neighbourhood of the Perissodaetyles, even of the Equidae ; it is so peculiar a character, and apparently so little related to any obvious similarity in way of life, that it seems to mark a special affinity. Not so the fact that in MaeraucJtenia at any rate the orbit was entirely surrounded by bone as in the Horse. "We find that condition so frequently acquired in many groups, — a development from an earlier condition where the cavity for the lodgment of the eye is in continuity with the temporal 1 See Osbons, Eull. Amer. Mus. XfoL Hist. vii. 1895, p, 82.